I haven't used the Polar mod but I think Vapresso's overall quality is pretty good. They are nice looking mods and have really fairly decent design and styling, I don't know that they are necessarily the most durable mods of all time, but I like them.
With that said, I have an Geekvape legend and I like it far more than any of my Vapresso mods, because it is designed to last. It's fairly heavy but has a nice handfeel, so that's not really burdensome.
I will say, ANY mod can fail, at any time. Although smok does have a bit of a reputation for QC issues, and for lack of durability, well, any mod can fail. Sometimes it's luck of the draw, sometimes it's user error, it can be a lot of things. There is also the Geekvape Ages, if you prefer a one battery mod, that is similarly durable.
If you have a removable battery mod, it's generally safest to charge using an external charger and will also cut down on wear and tear on a USB port, and with a dual battery mod, well, sometimes charging can be unbalanced which will put more strain on the batteries over time. There is also the convenience of being able to get more than one battery and to swap out batteries as you go, which can be nice.
You don't have to obtain all these things at once, and I think it's reasonable to get recommendations and whatnot. You can usually use any tank with any mod, provided they're both 510 attachments which are industry standard pretty much nowadays. So, you could say, get your mod, some batteries and a two bay charger and stay under 100 dollars US pretty much and get a decent set of equipment for that price, or you can buy as a kit, if one appeals to you and get the charger later.
Best of luck,
Anna